For sumac salt, combine ingredients in a bowl, season to taste with freshly ground pepper and set aside.
Preheat oven to 180°C/350°F; line a small baking sheet with foil.
Halve half of the tomatoes, place cut-side up on prepared sheet, drizzle with a little olive oil, season with a little sumac salt. Roast until tender (30-35 minutes). Set aside to cool.
Meanwhile, place wheat in a saucepan, cover generously with cold water and bring to the boil over medium-high heat. Reduce heat to medium and simmer until tender (35-40 minutes). Drain, refresh under cold running water, then drain well and set aside to cool.
Add olive oil and lemon juice (to taste) to the remaining sumac salt in order to make a dressing. Mix well.
Heat a non-stick frying pan over high heat. Fry the feta for 1–2 minutes each side or until golden. Chop into large pieces.
Halve the remaining tomatoes, mix with the roasted ones and place in a serving dish. Mix in the wheat, feta, basil and parsley. Drizzle with the dressing and serve.